1 ext4: fix ENOSPC handling in DAX page fault handler
3 From: Jan Kara <jack@suse.cz>
5 When allocation of underlying block for a page fault fails, we fail the
6 fault with SIGBUS. However we may well hit ENOSPC just due to lots of
7 free blocks being held by the running / committing transaction. So
8 propagate the error from ext4_iomap_begin() and implement do standard
9 allocation retry loop in ext4_dax_huge_fault().
11 Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
12 Signed-off-by: Jan Kara <jack@suse.cz>
13 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
15 fs/ext4/file.c | 10 ++++++++--
16 1 file changed, 8 insertions(+), 2 deletions(-)
18 diff --git a/fs/ext4/file.c b/fs/ext4/file.c
19 index 1c7cd882d998..fb6f023622fe 100644
22 @@ -280,7 +280,8 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
23 static int ext4_dax_huge_fault(struct vm_fault *vmf,
24 enum page_entry_size pe_size)
27 + int result, error = 0;
29 handle_t *handle = NULL;
30 struct inode *inode = file_inode(vmf->vma->vm_file);
31 struct super_block *sb = inode->i_sb;
32 @@ -304,6 +305,7 @@ static int ext4_dax_huge_fault(struct vm_fault *vmf,
33 sb_start_pagefault(sb);
34 file_update_time(vmf->vma->vm_file);
35 down_read(&EXT4_I(inode)->i_mmap_sem);
37 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
38 EXT4_DATA_TRANS_BLOCKS(sb));
40 @@ -314,9 +316,13 @@ static int ext4_dax_huge_fault(struct vm_fault *vmf,
42 down_read(&EXT4_I(inode)->i_mmap_sem);
44 - result = dax_iomap_fault(vmf, pe_size, &pfn, NULL, &ext4_iomap_ops);
45 + result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
47 ext4_journal_stop(handle);
49 + if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
50 + ext4_should_retry_alloc(sb, &retries))
52 /* Handling synchronous page fault? */
53 if (result & VM_FAULT_NEEDDSYNC)
54 result = dax_finish_sync_fault(vmf, pe_size, pfn);